Mng lm jup mik vs ak

a,
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
( 4x+3)^{2} -16x( x+6) +7( 10x+1) =0\\
\Leftrightarrow 16x^{2} +24x+9-16x^{2} -96x+70x+7=0\\
\Leftrightarrow -2x+16=0\\
\Leftrightarrow x=8
\end{array}$
b,
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
( 9-2x)^{2} -4( x+3)^{2} =81-24x\\
\Leftrightarrow 81-36x+4x^{2} -4\left( x^{2} +6x+9\right) =81-24x\\
\Leftrightarrow 81-36x+4x^{2} -4x^{2} -24x-36-81+24x=0\\
\Leftrightarrow -36x-36=0\\
\Leftrightarrow x=-1
\end{array}$
c,
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
( 9-2x)^{2} -4( x+3)^{2} =81-24x\\
\Leftrightarrow 81-36x+4x^{2} -4\left( x^{2} +6x+9\right) =81-24x\\
\Leftrightarrow 81-36x+4x^{2} -4x^{2} -24x-36-81+24x=0\\
\Leftrightarrow -36x-36=0\\
\Leftrightarrow x=-1
\end{array}$
d,
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
\left( x^{2} -1\right)^{2} -6( x-1)( x+1) =-9\\
\Leftrightarrow x^{4} -2x^{2} +1-6\left( x^{2} -1\right) +9=0\\
\Leftrightarrow x^{4} -2x^{2} +1-6x^{2} +6+9=0\\
\Leftrightarrow x^{4} -8x^{2} +16=0\\
\Leftrightarrow \left( x^{2} -4\right)^{2} =0\\
\Leftrightarrow x^{2} -4=0\\
\Leftrightarrow x^{2} =4\\
\Leftrightarrow x=\pm 2
\end{array}$